Francisco Javier Bonilla

• PhD
• PostDoc Position at CIC Energigune, Vitoria-Gasteiz

Li-metal-based batteries are considered as the next alternative to Li-ion batteries owing to their high specific capacity and energy density. Alleviating the use of liquid electrolytes, solid-state batteries using polymer electrolytes have gained vast attention. However, Li-metal solid-state batteries have major concerns regarding the non-total sup...

Solid polymer electrolytes offer a safer alternative to organic liquid electrolytes in high‐voltage lithium metal batteries, yet challenges remain in achieving adequate cyclability, energy density, scalability, and safety. This study presents the cycling performance of 1 Ah high‐voltage lithium polymer batteries featuring a hybrid ceramic polymer e...

Li metal secondary batteries known for their high energy and power density are the much-awaited energy storage systems owing to the high specific capacity of Li metal. However, due to the instability of Li metal with common Li-ion battery electrolytes, a combination with a polymer electrolyte seems to be an effective strategy to alleviate the safet...

Regarding the cost and safety concerns arising together with the increasing demands on Lithium-ion batteries (LIBs), high energy density Ni-rich LiNi0.8Co0.1Mn0.1O2 (NMC811) materials are of substantial interest as cathode materials for the next-generation commercial LIBs. However, their low cycling stability hinders their use in large-scale applic...

Graphite ineffectiveness in sodium storage has induced extensive research on non-graphitic carbons as high-performance active materials for negative electrodes of Na-ion batteries. Among these, soft carbons are promising for high-power sodium storage, yet their practical success is jeopardized by their low initial coulombic efficiency (i.e. 65-70%)...

Highly oriented thin‐film electrodes are the best playground to better understand the evolution of the electrode‐electrolyte interfaces during battery operation. This is crucial to develop next generation batteries. In this cover the authors represent Li ions (spheres) from the electrolyte (fog) reaching LTO electrode surface (SEM image) as in cell...

Among the electrodes for Li‐ion batteries, Li4Ti5O12 (LTO) stands out as anode owing to its stability and safety, in part ascribed to its low surface reactivity. However, the overlayer formation on the LTO surface upon electrochemical cycling is reported in recent years; a rough surface layer of electrochemically inactive α‐Li2TiO3 on top of the LT...

Solid polymer electrolytes (SPEs) with new functionalized ethyl cellulose bearing a lithium/sodium fluorosulfonylimide group (Ethyl cellulose-LiFSI/NaFSI) is proposed as quasi single ion (Li+/Na+) conducting polymer electrolyte for all-solid-state lithium and sodium batteries. The degree of ethyl cellulose functionalization by anion of lithium and...

The search for sodium ion battery cathodes has led to considerable interest in sodium layered oxides due to their attractive properties - e.g. flexibility, versatility, and intrinsically fast Na ion structural diffusion (leading to enhanced rate capability). Based upon our rational approach to material selection (i.e. doping a Mn-rich structure wit...

Herein, we report for the first time the use of TiSb2 alloy as anode material for sodium-ion batteries (NIBs) and capacitors (NICs). The electrochemical performance of TiSb2 in NIBs shows stable cycling with a capacity of about 225 mAh·g-1 for 200 cycles. Discrepancies with the expected theoretical specific charge are discussed by means of operando...

Sodium layered oxide materials have shown excellent performance as cathodes in sodium ion batteries, due to their flexibility, versatility, and intrinsically fast Na ion structural diffusion which leads to enhanced rate capability. In this work, we have examined two strategies to mitigate Jahn-Teller distortion and boost the performance of these sy...

Due to the limited Li resources, research on Na-ion batteries and capacitors is growing exponentially leading to the fast development of Na-based energy storage devices. When high energy density and power density are needed at the same time, hybridization between battery and supercapacitor electrodes can offer the figures of merit required. These d...

Sodium layered oxide materials show excellent performance as cathodes in sodium ion batteries, leading to considerable interest in routes to improving their properties. A manganese-rich P2/O3-phase Na2/3Li0.18Mn0.8Fe0.2O2 material is synthesized, from earth abundant precursors, via a solid state-reaction. Its biphasic nature is confirmed by X-ray d...

Flower and easy-axis vortex states are well-known magnetic configurations that can be stabilized in small particles. However, <111> vortex (V<111>), i.e. a vortex state with its core axis along the hard-axis direction, has been recently evidenced as a stable configuration in Fe nanocubes of intermediate sizes in the flower/vortex transition. In thi...

The different spin configurations in the vicinity of the single-domain/vortex transition are reported in isolated magnetic nanoparticles. By combining chemical synthesis, electron holography in a dedicated transmission electron microscope and micromagnetic simulations, we establish the "magnetic configuration vs size" phase diagram of Fe single-cry...

Strain engineering is a powerful tool to tailor the physical properties of materials coherently stacked in an epitaxial heterostructure. Such an approach, applied to the mature field of planar heteroepitaxy, has yielded a variety of new phenomena and devices. Recently, heteroepitaxial vertically aligned nanocomposites have emerged as alternatives t...

The magnetic anisotropy of 3-nm wide cobalt nanowires embedded in epitaxial CeO2/SrTiO3(001) layers is investigated by ferromagnetic resonance measurements. The measured magnetic shape and the magnetocrystalline anisotropies confirm that the Co nanowires have their main axes perpendicular to the film surface, and they are composed of hcp Co grains...

In this work, experimental results on the characterization of the structural, compositional, and magnetic properties of polycrystalline Tb Al MnO (x=0,0.05,0.07,0.1,0.2 , and 0.3 ) samples synthesized by means of standard solid-state reaction are reported. The most important effect of introducing Al in the crystal lattice of TbMnO is that it induce...

Self-assembled vertical epitaxial nanostructures form a new class of heterostructured materials that has emerged in recent years. Interestingly, such kind of architectures can be grown using combinatorial processes, implying sequential deposition of distinct materials. Although opening many perspectives, this combinatorial nature has not been fully...

The magnetic relaxation of Co nanowires assemblies embedded in CeO(2)/SrTiO(3)(001) epilayers has been investigated by magnetization decay measurements. Two different samples were studied, with nanowires having distinct crystallographic structures and diameters of 3 and 5 nm. The structure of the nanowires was derived from high-resolution transmiss...

Multiferroic materials exhibit, in the same phase, several ferric properties such as ferroelectricity, ferromagnetism, and ferroelasticity, which are coupled each to other. In this work, we synthesized polycrystalline Tb1−x Alx MnO3 (x=0, 0.05, 0.07, 0.1, and 0.3) by standard solid-state reaction. The starting precursors Tb4O7, MnO2, Al2O3 were sto...

DOI:https://doi.org/10.1103/PhysRevLett.109.139901

The mechanism of magnetization reversal has been studied in a model system of self-assembled cobalt nanowires with a 3 nm diameter. The structure, orientation and size of grains within the nanowires could be determined by high resolution transmission electron microscopy. The magnetic properties were probed using static and dynamic magnetization mea...

Sequential pulsed laser deposition of CoO and CeO2 at 650 °C under vacuum leads to the formation of a slanted Co nanowires assembly embedded in CeO2/SrTiO3(0 0 1) epilayers. High temperature magneto-optical Faraday measurements were performed, which revealed a Faraday ellipticity of 1.3° at a wavelength of 450 nm for 300 nm thick samples and which...

The mechanism of magnetization reversal has been studied in a model system of self-assembled cobalt nanowires with 3 nm diameter. The structure, orientation and size of grains within the nanowires could be determined by high resolution transmission electron microscopy. The magnetic properties were probed using static and dynamic magnetization measu...